66 Restoration - Break Problem

[Ron N.]

[Bill W.]

Re: 66 Restoration - Break Problem

Ron, You either have air in the system which was not removed during bleeding or the rebuild master cylinder is leaking internally. Since you can't develop any pressure to bleed with the brake pedal try gravity bleeding one wheel at a time. Start at left rear and open the inside bleed valve, use clear TYGON tubing so you can see what is coming out, at some point in time fluid will begin to flow. Go to outer valve and repeat. This may take some time, don't let master cylinder go dry. If after several trys you have no luck I think it's time for a pressure bleeder. Good luck, Bill

[William C.]

Re: 66 Restoration - Break Problem

I'm with Bill, use a pressure bleeder, work from the pass rear to drivers rear, then pass front and driver front. If the problem persists, then I'd start looking at the master cyl. Is the pushrod set to the correct length?

[Robert S.]

Re: 66 Restoration - Break Problem

I think the system is like the C3 which I am familiar and I had a similar problem. The root cause iwas that the rear brakes have two fittings to bleed on each side (inner and outer) and I was only bleeding the inner. Once I realized there was an outer to bleed, I got a firm petal on the first try.

[Harry S.]

Re: 66 Restoration - Break Problem

I know your MC is much different than my 63 but I had a similar problem. To eliminate the MC, I disconnect the brake line and put a bolt (proper threads) in the brake line hole. I had a firm pedal. I ended up finding a bad wheel cylinder and air in the line.

[Ron N.]

Re: 66 Restoration - Break Problem

Thanks guys. We did a gravity bleed but not in the sequence you discribed. We'll try it again and if that dosen't work we will replace the master cylinder with a spare have.

I'll post the results (hopefully sucessful) for anyone interested.

Thanks,
Ron

[Ron N.]

Re: 66 Restoration - Break Problem

Problem finally resolved by replacing the break fluid from silicone to DOT 3.

Things initially tried without results:
-Rebuilt MC 2 times
-Rebuilt calipers (SS sleeves)
-Tested booster
-Inspected lines (no leaks)
-Checked vacuumed
-Bleed lines - many times vacuumed & gravity (correct sequence)

Thanks for all the suggestion and help.